noise rear wheel 1999-E36 .....HELP

bought car this afternoon, test drove car 5 miles average speed 35MPH car ran great...forgot to release emergency brake, did not notice as car did not hesitate at all. drove home 200 miles with emergency brake released, did not think there would be a problem. in the last 10 miles drivers side rear wheel developed a tinney whiney sound that increases with speed. got home check out rear pads they are about l/4" thick, can not see inboard, both rear rotors have blueish tint in center. It is not making a grinding sound that I would associate with a wheel bearing. so are all four rear pads activated when emergency lever is pulled up:? what it sounds like is a piece of tin rubbing against rotor like when pads are worn down in some cars you would get this warning sound. I was thinking of jacking up both rear wheels with tires off and running car in gear to see if this can be isolated. any help would be appreciated

I had the above sound in my bimmer (drivers side rear) and tried everything a normal - non indy - would do to fix it and it wouldnt go away (replaced pads, checked dust cover, tried ebrake while rolling to reseat it etc).

Thought it had to be rear wheel bearings so I got them, and took the car down to my mechanic. He removed both back wheels, then the calipers, and then the hubs. The drivers side rear hub was a pia to remove and had to be soaked in PB blaster for like 2 days and then beaten to take off it had so much corrosion it looked like a WW2 souvenir. After removing it we found the problem. The springs that holds the e-brake in place were missing and this caused the e-brake to slide further into the channel than it needed to. This caused the ebrake to grind inside the hub and therefore produced the sound I heard. According to my indy this was a bad accident waiting to happen cos it wouldnt have taken much to completely seize the wheel while i was driving. It also caused undue wear on the wheel bearing and because of the inconsistent wheel speed was caused my abs light to trigger periodically (with no codes on the obd2 scanner). Long story short, springs replaced, rear wheel bearings replaced, e-brake adjusted and the car is my pride and joy again. I hope this may help someone else out there with a similar issue since that is ultimately what great forums such as this are for (if we ignore the negative chumps that also lurk on them). Keep driving :-).